Progesterone Signaling Research Articles

Decidualized endometrial stromal cells present with altered androgen response in PCOS

Hyperandrogenic women with PCOS show disrupted decidualization (DE) and placentation. Dihydrotestosterone (DHT) is reported to enhance DE in non-PCOS endometrial stromal cells (eSCCtrl); however, this has not been assessed in PCOS cells (eSCPCOS). Therefore, we studied the transcriptome profile of non-decidualized (non-DE) and DE eSCs from women with PCOS and Ctrl in response to short-term estradiol (E2) and/or progesterone (P4) exposure with/without (±) DHT. The non-DE eSCs were subjected to E2 ± DHT treatment, whereas the DE (0.5 mM 8-Br-cAMP, 96 h) eSCs were post-treated with E2 and P4 ± DHT, and RNA-sequenced. Validation was performed by immunofluorescence and immunohistochemistry. The results showed that, regardless of treatment, the PCOS and Ctrl samples clustered separately. The comparison of DE vs. non-DE eSCPCOS without DHT revealed PCOS-specific differentially expressed genes (DEGs) involved in mitochondrial function and progesterone signaling. When further adding DHT, we detected altered responses for lysophosphatidic acid (LPA), inflammation, and androgen signaling. Overall, the results highlight an underlying defect in decidualized eSCPCOS, present with or without DHT exposure, and possibly linked to the altered pregnancy outcomes. We also report novel factors which elucidate the mechanisms of endometrial dysfunction in PCOS.

Progesterone Receptors in AVPV Kisspeptin Neurons Are Sufficient for Positive Feedback Induction of the LH Surge.

Kisspeptin, encoded by Kiss1, stimulates gonadotropin-releasing hormone neurons to govern reproduction. In female rodents, estrogen-sensitive kisspeptin neurons in the rostral anteroventral periventricular (AVPV) hypothalamus are thought to mediate estradiol (E2)-induced positive feedback induction of the preovulatory luteinizing hormone (LH) surge. AVPV kisspeptin neurons coexpress estrogen and progesterone receptors (PGRs) and are activated during the LH surge. While E2 effects on kisspeptin neurons have been well studied, progesterone's regulation of kisspeptin neurons is less understood. Using transgenic mice lacking PGR exclusively in kisspeptin cells (termed KissPRKOs), we previously demonstrated that progesterone action specifically in kisspeptin cells is essential for ovulation and normal fertility. Unlike control females, KissPRKO females did not generate proper LH surges, indicating that PGR signaling in kisspeptin cells is required for positive feedback. However, because PGR was knocked out from all kisspeptin neurons in the brain, that study was unable to determine the specific kisspeptin population mediating PGR action on the LH surge. Here, we used targeted Cre-mediated adeno-associated virus (AAV) technology to reintroduce PGR selectively into AVPV kisspeptin neurons of adult KissPRKO females, and tested whether this rescues occurrence of the LH surge. We found that targeted upregulation of PGR in kisspeptin neurons exclusively in the AVPV is sufficient to restore proper E2-induced LH surges in KissPRKO females, suggesting that this specific kisspeptin population is a key target of the necessary progesterone action for the surge. These findings further highlight the critical importance of progesterone signaling, along with E2 signaling, in the positive feedback induction of LH surges and ovulation.

P-322 Addressing progesterone and cAMP signalling pathways for decidualization induction of endometrial stromal cells of patients with endometriosis

Abstract Study question Which compounds/compound combinations are most effective in decidualization induction of endometrial stromal cells (ESCs) of patients with and without endometriosis? Summary answer Combination of compounds addressing different steps in the signalling cascade of decidualization induce decidualization more effectively than application of the individual compounds alone. What is known already Decidualization is the monthly recurring differentiation process of the ESCs in preparation for embryo implantation in human. Undifferentiated ESCs reveal an increased potential to proliferate and invade after retrograde menstruation. This may lead to the formation of ectopic lesions and the manifestation of the chronic gynaecological disease of endometriosis due to an impairment of the decidualization process. Study design, size, duration Compounds and compound combinations addressing the progesterone receptor- or the cAMP-mediated pathway were evaluated with regard to their own and their synergistic potential to induce decidualization of ESCs from women with (n = 10) and without (n = 10) endometriosis during a 6-day treatment. Participants/materials, setting, methods Human primary ESCs were isolated via enzymatic-mechanic digestion from eutopic endometrium from women with and without endometriosis and treated for 6 days in vitro with different progestins (progesterone, medoxyprogesterone acetate (MPA)), 8-Br-cAMP, forskolin, or phosphodiesterase (PDE)-inhibitor (Rolipram) alone or in combination. The degree of decidualization induction was quantified by morphological, biochemical (prolactin) and molecular (HAND2, FOXO1) parameters by means of ELISA, flow cytometric analysis, Realtime PCR and Western blot analysis. Main results and the role of chance After 6 days of treatment, decidualization was induced by forskolin as well as by 8-Br-cAMP whereas progestins or PDE alone hardly induced prolactin secretion by ESCs as a marker of decidualization. A change of morphology from undifferentiated fibroblast-like cells to rounded cells could be observed in parallel with the secretion of prolactin. Forskolin and 8-Br-cAMP-induced decidualization was significantly enhanced by MPA but not by progesterone. These effects were similar in ESCs from women with and without endometriosis. Moreover, forskolin-induced decidualization was significantly enhanced by simultaneous application of PDE. Interestingly, this effect was higher in cells of patients with endometriosis. An induction of decidualization in ESCs was associated with a parallel increase of the process-associated transcription factors HAND2 and FOXO1. This rise of transcription was markedly increased in combination with MPA but not with progesterone. Limitations, reasons for caution Endometrial tissue was obtained from women undergoing infertility treatment and thus may differ from the endometrium of fertile women. Results obtained from primary cells in vitro may not cover the in vivo situation in all respects. Wider implications of the findings The results of this study provide baseline data for the development of a possible therapeutical approach to induce decidualization as a treatment option for endometriosis. Further research is required to determine the effectiveness of the in vitro tested compound combinations in an in vivo model. Trial registration number not applicable

P–322 Addressing progesterone and cAMP signalling pathways for decidualization induction of endometrial stromal cells of patients with endometriosis

Abstract Study question Which compounds/compound combinations are most effective in decidualization induction of endometrial stromal cells (ESCs) of patients with and without endometriosis? Summary answer Combination of compounds addressing different steps in the signalling cascade of decidualization induce decidualization more effectively than application of the individual compounds alone. What is known already Decidualization is the monthly recurring differentiation process of the ESCs in preparation for embryo implantation in human. Undifferentiated ESCs reveal an increased potential to proliferate and invade after retrograde menstruation. This may lead to the formation of ectopic lesions and the manifestation of the chronic gynaecological disease of endometriosis due to an impairment of the decidualization process. Study design, size, duration Compounds and compound combinations addressing the progesterone receptor- or the cAMP-mediated pathway were evaluated with regard to their own and their synergistic potential to induce decidualization of ESCs from women with (n = 10) and without (n = 10) endometriosis during a 6-day treatment. Participants/materials, setting, methods Human primary ESCs were isolated via enzymatic-mechanic digestion from eutopic endometrium from women with and without endometriosis and treated for 6 days in vitro with different progestins (progesterone, medoxyprogesterone acetate (MPA)), 8-Br-cAMP, forskolin, or phosphodiesterase (PDE)-inhibitor (Rolipram) alone or in combination. The degree of decidualization induction was quantified by morphological, biochemical (prolactin) and molecular (HAND2, FOXO1) parameters by means of ELISA, flow cytometric analysis, Realtime PCR and Western blot analysis. Main results and the role of chance After 6 days of treatment, decidualization was induced by forskolin as well as by 8-Br-cAMP whereas progestins or PDE alone hardly induced prolactin secretion by ESCs as a marker of decidualization. A change of morphology from undifferentiated fibroblast-like cells to rounded cells could be observed in parallel with the secretion of prolactin. Forskolin and 8-Br-cAMP-induced decidualization was significantly enhanced by MPA but not by progesterone. These effects were similar in ESCs from women with and without endometriosis. Moreover, forskolin-induced decidualization was significantly enhanced by simultaneous application of PDE. Interestingly, this effect was higher in cells of patients with endometriosis. An induction of decidualization in ESCs was associated with a parallel increase of the process-associated transcription factors HAND2 and FOXO1. This rise of transcription was markedly increased in combination with MPA but not with progesterone. Limitations, reasons for caution Endometrial tissue was obtained from women undergoing infertility treatment and thus may differ from the endometrium of fertile women. Results obtained from primary cells in vitro may not cover the in vivo situation in all respects. Wider implications of the findings: The results of this study provide baseline data for the development of a possible therapeutical approach to induce decidualization as a treatment option for endometriosis. Further research is required to determine the effectiveness of the in vitro tested compound combinations in an in vivo model. Trial registration number Not applicable

P–293 Ovarian endometriomas are heterogenous for the steroidogenic function and the expression of estrogen and progesterone receptors

Abstract Study question Do all ovarian endometriomas have steroidogenic function and express estrogen and progesterone receptors? Summary answer No, they are heterogenous for the steroidogenic function and the expression of the estrogen and progesterone receptors. What is known already Excessive ectopic estrogen production and up-regulation of estrogen receptor- β, which drives inflammation together with aberrant progesterone signaling leading to impaired decidualization and establishment of ectopic endometrial implants together with down-regulated progesterone receptor (PR) expression are the cardinal molecular features of the disease. However, several fundamental questions still remain to be answered as to whether all ovarian endometriomas carry these molecular aberrations and are steroidogenically active; and if so, the amount of sex steroids they produce correlate with the level of expression of steroidogenic enzymes. We aimed to address these questions in the current study. Study design, size, duration A molecular research study on the surgical specimens collected between April 2020 and December 2020. Seven histopathologically confirmed benign endometriotic cyst capsules obtained from the patients undergoing laparoscopic excision of unilateral ovarian endometriomas without deep infiltrating endometriosis during early follicular phase were used in the study. Participants/materials, setting, methods The mean age±SD (range) of the patients were 32.8±4.9 (30–39). The mean endometrioma size was 5±1.2cm (5–7.5 cm). The samples were cut into equal size pieces of 0.5x0.5cm size and cultured for one day to measure their E2and P4production; and analyzed for the expression of steroidogenic enzymes with quantitative immunoblotting and for the expression of FSH-R, ER and PR with real-time qRT-PCR methods. Luteinized granulosa cells and ovarian cortex were set as references. Main results and the role of chance StAR expression was consistently observed in all samples. However, we noticed significant discrepancies among the samples regarding their steroidogenic function and the expression of aromatase and 3 β-HSD enzymes. E2 production exhibited significant variation (from 5 to 1177pg/mL) from sample to sample despite comparable levels of aromatase expression. ER- βup-regulation as a cardinal molecular feature of endometriosis, was observed in all but one samples (1.46 to 5.48 folds, p < 0.0001). However, its expression level did not correlate with either aromatase expression or the amount of E2 the samples produced. A similar phenomenon was observed in P4 arm of steroidogenesis. Even though 3 β-HSD was expressed by all but one samples detectable amount of P4 was produced only by two samples (up to 15ng/mL). PR expression was down-regulated only in two samples (0.3 to 0.07 folds, p < 0.0001), and significantly up-regulated in the other samples (1.2 to 4.7 folds, p < 0.001). No correlation was found among the samples regarding the expression of PR, 3 β-HSD and P4 output. FSH-R was detected in all samples at the levels comparable to ovarian cortex but its expression level did not show any correlation with ER, aromatase expression and E2 production. Limitations, reasons for caution These results need to be confirmed in studies with larger sample size and different types of endometriotic lesions. Wider implications of the findings: The regulation of steroidogenic activity of endometriomas cannot simply be explained by the expression level of the steroidogenic enzymes, underscoring the importance of other mechanisms that post-translationally regulate their enzymatic activity and metabolism of estrogen and progesterone. PR is not always down-regulated and FSH-R is commonly up-regulated in ovarian endometriomas. Trial registration number Not applicable

Progesterone signalling is involved in marsupial pregnancy

Progesterone signalling is involved in marsupial pregnancy

Progesterone signalling is involved in marsupial pregnancy

Progesterone signalling is involved in marsupial pregnancy

Mechanism of Action of Irilone as a Potentiator of Progesterone Receptor Signaling

Progesterone signaling and its proper regulation is important for reproductive function. When progesterone signaling is dysregulated, gynecological diseases can occur, for example endometriosis, uterine fibroids, and endometrial cancer. While these diseases are treated with progestin therapy, progestins can bind to multiple steroid receptors, exerting side effects of weight gain, immunosuppression, cardiovascular disease, and stroke. Discovering an alternative progestin that is selective for the progesterone receptor (PR) is ideal. One potential source of such an alternative is botanical dietary supplements, which have become increasingly popular among consumers with sales reaching $9.6 billion in 2019. Although botanical supplements are popular, the chemical structures and biological action of botanical supplements would benefit from deeper scientific investigation. Studies of Trifolium pratense L. (red clover), primarily used for the treatment of menopausal symptoms, identified phytoestrogen compounds as the chemicals that mitigate those symptoms. Interestingly, irilone, identified from red clover, potentiated progesterone signaling via a progesterone response element luciferase (PRE/Luc) assay. Potentiation is when a compound has no activity by itself but when combined with another molecule, i.e. progesterone, that compound enhances PR activity. Prior to irilone, a natural compound with the ability to potentiate progesterone signaling had not been previously reported. The purpose of this study was to determine the mechanism of action of irilone. We hypothesized that irilone was potentiating PR by blocking PR degradation and by altering PR post-translational modifications. Irilone was found to potentiate 5 nM P4 using a PRE-luciferase assay in both T47D and Ishikawa PR expressing cells. Since PR is a downstream target gene of ER, we investigated if irilone also had ER activity. Irilone increased expression of an ERE-luciferase reporter gene. Next, we investigated if irilone could stabilize PR degradation and if irilone altered PR phosphorylation via western blot. Irilone was found to increase PR protein levels, but when ER was blocked, this was mitigated. In the presence of P4, irilone did not increase phosphorylation of serine 294 on PR. Future studies will determine if irilone is altering sumoylation of PR, and if irilone can potentiate PR signaling in vivo. Determining how irilone is potentiating progesterone will help us understand PR biology and could be an effective treatment for gynecological diseases by enhancing endogenous progesterone action.

Differential Genomic Interactions Drive Progesterone Receptor Isoform Specific Functions in Breast Cancer

Progesterone is critical for normal breast development and function, and has been shown to stimulate proliferation of normal breast epithelial cells by increasing stem and progenitor cell numbers. Breast cancer incidence is increased in women exposed to progesterone analogues in combined estrogen plus progestin hormone replacement therapy, but not in women taking estrogen alone. Classical progesterone signaling is mediated through the nuclear progesterone receptor (PR), which occurs as two related but functionally different isoforms, PRA and PRB. PRA and PRB are co-expressed equally in normal breast tissue but become dysregulated in breast cancer where PRA often becomes predominant. PRA predominance in breast cancer is associated with poorer outcome and higher risk of distant metastasis in tamoxifen treated patients. We show using integrated analysis of ChIP-seq, ATAC-seq and transcriptomic profiling in a breast cancer cell line model of acquired PRA predominance that: 1) PRA and PRB have different requirements with regard to chromatin accessibility; 2) PRA predominance reshapes the PR cistrome and the associated transcriptome to affect genes not normally regulated by PR when PRA and PRB are equivalently expressed, possibly through assisted loading with multiple other transcription factors; 3) Genes regulated by PR only when PRA is predominant are associated with poorer breast cancer outcome and involved in multiple cancer-associated pathways including those that regulate cell proliferation and adhesion. Our data suggest a mechanism for the poorer disease outcome seen in breast cancers with a predominance of PRA.

Illuminating the "Black Box" of Progesterone-Dependent Embryo Implantation Using Engineered Mice.

Synchrony between progesterone-driven endometrial receptivity and the arrival of a euploid blastocyst is essential for embryo implantation, a prerequisite event in the establishment of a successful pregnancy. Advancement of embryo implantation within the uterus also requires stromal fibroblasts of the endometrium to transform into epithelioid decidual cells, a progesterone-dependent cellular transformation process termed decidualization. Although progesterone is indispensable for these cellular processes, the molecular underpinnings are not fully understood. Because human studies are restricted, much of our fundamental understanding of progesterone signaling in endometrial periimplantation biology comes from in vitro and in vivo experimental systems. In this review, we focus on the tremendous progress attained with the use of engineered mouse models together with high throughput genome-scale analysis in disclosing key signals, pathways and networks that are required for normal endometrial responses to progesterone during the periimplantation period. Many molecular mediators and modifiers of the progesterone response are implicated in cross talk signaling between epithelial and stromal cells of the endometrium, an intercellular communication system that is critical for the ordered spatiotemporal control of embryo invasion within the maternal compartment. Accordingly, derailment of these signaling systems is causally linked with infertility, early embryo miscarriage and gestational complications that symptomatically manifest later in pregnancy. Such aberrant progesterone molecular responses also contribute to endometrial pathologies such as endometriosis, endometrial hyperplasia and cancer. Therefore, our review makes the case that further identification and functional analysis of key molecular mediators and modifiers of the endometrial response to progesterone will not only provide much-needed molecular insight into the early endometrial cellular changes that promote pregnancy establishment but lend credible hope for the development of more effective mechanism-based molecular diagnostics and precision therapies in the clinical management of female infertility, subfertility and a subset of gynecological morbidities.

Disturbed progesterone signalling in an advanced preclinical model of endometriosis

Research questionDo human endometriosis organoids recapitulate aberrant progesterone signalling in the disease to serve as advanced experimental models for uncovering epigenetic mechanisms involved in attenuated progesterone response in endometriosis? DesignInitially, the organoids were established from acquired biopsies (women with and without endometriosis) and characterized by morphological, histological and immunostaining analyses. Results: A panel of endometriosis-related genes showed a pattern of expressions in cytochrome c oxidase subunit II (COX2), matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase-3 (TIMP3), transforming growth factor beta 1 (TGF-β1), and zinc finger E-box binding homeobox 1 (ZEB1), and a contradictory expression pattern for cadherin (CDH1), POU class 5 homeobox 1 (POU5F1; also known as OCT4), and Nanog homeobox (NANOG) in the endometriosis organoids that is concordant with published research. These endometriosis organoids failed to upregulate 17β-Hydroxysteroid dehydrogenase 2 (17HSDβ2), progestogen associated endometrial protein (PAEP), secreted phosphoprotein 1 (SPP1), and leukaemia inhibitory factor (LIF) in response to progesterone at the level observed in control endometrium organoids. Progesterone receptor B (PRB) gene expression significantly decreased in both eutopic and ectopic organoids compared with control endometrium organoids. DNA hypermethylation, as an epigenetic mechanism for suppression of transcription, was detected at the PRB promoter in the eutopic, but not ectopic, organoids. Therefore, other epigenetic mechanisms, such as histone modifications and microRNAs, may be responsible for PRB downregulation in ectopic organoids. ConclusionsEndometriosis organoids are powerful preclinical models that can be used to investigate the molecular mechanisms involved in endometriosis-associated progesterone resistance.

Role of the androgen, estrogen, and progesterone receptors in adherent perinephric fat in robotic partial nephrectomy

To determine whether androgen, estrogen, and/or progesterone signaling play a role in the pathophysiology of adherent perinephric fat (APF). We prospectively recruited patients undergoing robotic assisted partial nephrectomy during 2015-2017. The operating surgeon documented the presence or absence of APF. For those with clear cell renal cell carcinoma (ccRCC), representative sections of tumor and perinephric fat were immunohistochemically stained with monoclonal antibody to estrogen α, progesterone, and androgen receptors. Patient characteristics, operative data, and hormone receptor presence were compared between those with and without APF. Of 51 patients total, 18 (35.3%) and 33 (64.7%) patients did and did not have APF, respectively. APF was associated with history of diabetes mellitus (61.1% vs 24.2%, p = 0.009) and larger tumors (4.0cm vs 3.0cm, p = 0.017) but not with age, gender, BMI, Charleston comorbidity index, smoking, or preoperative estimated glomerular filtration rate. APF was not significantly associated with length of operation, positive margins, or 30-day postoperative complications but incurred higher estimated blood loss (236.5mL vs 209.2mL, p = 0.049). Thirty-two had ccRCC and completed hormone receptor staining. The majority of tumors and perinephric fat were negative for estrogen and progesterone while positive for androgen receptor expression. There was no difference in hormone receptor expression in either tumor or perinephric fat when classified by presence or absence of APF (p > 0.05). APF is more commonly present in patients with diabetes or larger tumors but was not associated with differential sex hormone receptor expression in ccRCC.

Progesterone Receptor Signaling in the Breast Tumor Microenvironment.

The tumor microenvironment (TME) is a complex infrastructure composed of stromal, epithelial, and immune cells embedded in a vasculature ECM. The microenvironment surrounding mammary epithelium plays a critical role during the development and differentiation of the mammary gland, enabling the coordination of the complex multihormones and growth factor signaling processes. Progesterone/progesterone receptor paracrine signaling interactions in the microenvironment play vital roles in stem/progenitor cell function during normal breast development. In breast cancer, the female sex hormones, estrogen and progesterone, and growth factor signals are altered in the TME. Progesterone signaling modulates not only breast tumors but also the breast TME, leading to the activation of a series of cross-communications that are implicated in the genesis of breast cancers. This chapter reviews the evidence that progesterone and PR signaling modulates not only breast epitheliums but also the breast TME. Furthermore, crosstalk between estrogen and progesterone signaling affecting different cell types within the TME is discussed. A better understanding of how PR and progesterone affect the TME of breast cancer may lead to novel drugs or a therapeutic approach for the treatment of breast cancer shortly.

Targeting progesterone signaling prevents metastatic ovarian cancer.

Effective cancer prevention requires the discovery and intervention of a factor critical to cancer development. Here we show that ovarian progesterone is a crucial endogenous factor inducing the development of primary tumors progressing to metastatic ovarian cancer in a mouse model of high-grade serous carcinoma (HGSC), the most common and deadliest ovarian cancer type. Blocking progesterone signaling by the pharmacologic inhibitor mifepristone or by genetic deletion of the progesterone receptor (PR) effectively suppressed HGSC development and its peritoneal metastases. Strikingly, mifepristone treatment profoundly improved mouse survival (∼18 human years). Hence, targeting progesterone/PR signaling could offer an effective chemopreventive strategy, particularly in high-risk populations of women carrying a deleterious mutation in the BRCA gene.

Secretory phospholipase A2-X (Pla2g10) is a novel progesterone receptor target gene exclusively induced in uterine luminal epithelium for uterine receptivity in mice

BackgroundAberration of estrogen (E2) and/or progesterone (P4) signaling pathways affects expression of their target genes, which may lead to failure of embryo implantation and following pregnancy. Although many target genes of progesterone receptors (PRs) have been identified in uterine stroma, only a few PR targets have been reported in the epithelium. Secretory phospholipase A2-(PLA2)-X, a member of the PLA2 family that releases arachidonic acids for the synthesis of prostaglandins that are important for embryo implantation, is dysregulated in the endometrium of patients suffering from repeated implantation failure. However, it is not clear whether sPLA2-X is directly regulated by ovarian steroid hormones for embryo implantation in the uterus.ResultP4 induced the Pla2g10 encoding of secretory PLA2-X in the apical region of uterine LE of ovariectomized mice via PR in both time- and dose-dependent manners, whereas E2 significantly inhibited it. This finding is consistent with the higher expression of Pla2g10 at the diestrus stage, when P4 is elevated during the estrous cycle, and at P4-treated delayed implantation. The level of Pla2g10 on day 4 of pregnancy (day 4) was dramatically decreased on day 5, when PRs are absent in the LE. Luciferase assays of mutagenesis in uterine epithelial cells demonstrated that four putative PR response elements in a Pla2g10 promoter region are transcriptionally active for Pla2g10. Intrauterine delivery of small interfering RNA for Pla2g10 on day 3 significantly reduced the number of implantation sites, reinforcing the critical function(s) of Pla2g10 for uterine receptivity in mice.ConclusionsPla2g10 is a novel PR target gene whose expression is exclusively localized in the apical region of the uterine LE for uterine receptivity for embryo implantation in mice.

Mixed-lineage leukaemia 1 contributes to endometrial stromal cells progesterone responsiveness during decidualization.

Studies have reported that non‐receptive endometrium or abnormal decidualization was closely related to recurrent implantation failure (RIF). MLL1 is a histone H3 lysine 4 trimethylation (H3K4me3) transferase that regulates the transcriptional activation of target genes. The role of MLL1 has been underexplored during decidualization. In our research, we found the expression of MLL1 was closely related to endometrial receptivity, and it was responsible to hormone stimulation. Inhibiting the function of MLL1 by MM102 reduced the transformation of HESCs. Furthermore, down‐regulation of MLL1 by siRNA transfection significantly decreased PGR and its target genes expression. MLL1 act as a co‐activator of ERα, and both of them were recruited to PGR regulatory regions, thus promote PGR transcription. Our study showed that MLL1 plays a key role in promoting progesterone signalling transmission.

The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies.

Meningiomas are the most common primary intracranial tumor with current classification offering limited therapeutic guidance. Here, we interrogated meningioma enhancer landscapes from 33 tumors to stratify patients based upon prognosis and identify novel meningioma-specific dependencies. Enhancers robustly stratified meningiomas into three biologically distinct groups (adipogenesis/cholesterol, mesodermal, and neural crest) distinguished by distinct hormonal lineage transcriptional regulators. Meningioma landscapes clustered with intrinsic brain tumors and hormonally responsive systemic cancers with meningioma subgroups, reflecting progesterone or androgen hormonal signaling. Enhancer classification identified a subset of tumors with poor prognosis, irrespective of histologic grading. Superenhancer signatures predicted drug dependencies with superior in vitro efficacy to treatment based upon the NF2 genomic profile. Inhibition of DUSP1, a novel and druggable meningioma target, impaired tumor growth in vivo. Collectively, epigenetic landscapes empower meningioma classification and identification of novel therapies. SIGNIFICANCE: Enhancer landscapes inform prognostic classification of aggressive meningiomas, identifying tumors at high risk of recurrence, and reveal previously unknown therapeutic targets. Druggable dependencies discovered through epigenetic profiling potentially guide treatment of intractable meningiomas.This article is highlighted in the In This Issue feature, p. 1611.

Proceedings from the Fourth International Symposium on σ-2 Receptors: Role in Health and Disease.

The σ-2 receptor (S2R) complex has been implicated in CNS disorders ranging from anxiety and depression to neurodegenerative disorders such as Alzheimer’s disease (AD). The proteins comprising the S2R complex impact processes including autophagy, cholesterol synthesis, progesterone signaling, lipid membrane-bound protein trafficking, and receptor stabilization at the cell surface. While there has been much progress in understanding the role of S2R in cellular processes and its potential therapeutic value, a great deal remains unknown. The International Symposium on Sigma-2 Receptors is held in conjunction with the annual Society for Neuroscience (SfN) conference to promote collaboration and advance the field of S2R research. This review summarizes updates presented at the Fourth International Symposium on Sigma-2 Receptors: Role in Health and Disease, a Satellite Symposium held at the 2019 SfN conference. Interdisciplinary members of the S2R research community presented both previously published and preliminary results from ongoing studies of the role of S2R in cellular metabolism, the anatomic and cellular expression patterns of S2R, the relationship between S2R and amyloid β (Aβ) in AD, the role of S2R complex protein PGRMC1 in health and disease, and the efforts to design new S2R ligands for the purposes of research and drug development. The proceedings from this symposium are reported here as an update on the field of S2R research, as well as to highlight the value of the symposia that occur yearly in conjunction with the SfN conference.

Abstract P210: Progesterone Induced Blocking Factor Blockade Increases Inflammation And Markers Of Endothelial Dysfunction In Pregnant Rats

Preeclampsia (PE) is a leading cause of maternal and perinatal morbidity in the U.S. While the pathogenesis remains unclear, PE is characterized by new onset hypertension associated with progesterone deficiency, elevated cytolytic natural killer cells (cNK), inflammation, and endothelial dysfunction. Progesterone is essential in the initiation and maintenance of pregnancy. We have shown that progesterone supplementation regulates endothelial function and suppresses endothelin-1 (ET-1) and stimulates nitric oxide (NO) in response to placental ischemia during pregnancy. In addition, progesterone signals the synthesis and release of progesterone induced blocking factor (PIBF) from lymphocytes in order to regulate the proinflammatory balance of early pregnancy. However the role of PIBF in PE pathology is not well examined. This study was designed to test the hypothesis that inhibition of PIBF causes inflammation and increases markers of endothelial dysfunction and hypertension during pregnancy. Rabbit anti-PIBF IgG (0.25, low dose-LD or 0.50 mg/mL, high dose-HD) was administered intraperitoneal on gestation day (GD) 15 to normal pregnant Sprague Dawley (NP) rats, on GD 18 carotid catheters were inserted and on GD 19 blood pressure (MAP) and samples were collected. MAP in NP rats (n=7) was 99 + 3 mmHg, which increased to 116 + 2 in NP+ anti-PIBF LD (n =10) and 113 + 4 mmHg in NP+ anti-PIBF HD (n=6), p<0.05. Plasma TNF-alpha levels were 35 + 8 pg/mL in NP rats and increased to 84 + 21 pg/mL in NP+ Anti-PIBF HD (n=4), p<0.05. Circulating total NK cells were 67 + 11 in NP rats (n=4), which decreased to 36 + 4 in NP+ Anti-PIBF HD however, cytolytic NK cells were 0.6 + 0.2 in NP which were increased to 3.0 + 1 in NP+ Anti-PIBF HD, p<0.05. Importantly, circulating NO levels were 44 + 11 μM in NP rats (n=5), which significantly decreased to 21 + 1 μM in NP+ Anti-PIBF (n=6) HD, p<0.05. Moreover, renal cortex PPET-1 levels increased 15 fold in NP+ Anti-PIBF (n=6) HD compared to NP rats (n=5). Our study demonstrates that PIBF blockade causes hypertension and inflammation and signs of endothelial dysfunction, all of which are associated with PE, thus indicating the importance of progesterone signaling pathways during healthy pregnancy.

Abstract P222: Progesterone Induced Blocking Factor Decreases Hypertension, Mitochondrial Dysfunction And Reactive Oxygen Species In Response To Elevated Sflt-1 During Pregnancy

Preeclampsia (PE) is characterized by new onset hypertension in association with placental ischemia, reduced fetal weight, elevated soluble fms-like tyrosine kinase-1 (sFlt-1) and placental mitochondrial (mt) dysfunction and oxidative stress (ROS). Infusion of sFlt-1 causes hypertension and other characteristics of PE in pregnant rodents. However a role for sFlt-1 in causing mt dysfunction and ROS is unknown. Progesterone induced blocking factor (PIBF), is a product of progesterone signaling which lowers inflammatory processes. We have shown that PIBF lowers blood pressure in a rat models of PE. This study was designed not only examine the role of mt ROS in sFlt-1 induced hypertension during pregnancy but to also examine the effect of PIBF to improve mt function and hypertension in response to elevated sFlt-1 during pregnancy. sFlt-1 was infused into normal pregnant (NP) Sprague-Dawley rats (3.7 μg·kg –1 ·day –1 for 6 days, gestation days (GD) 13-19 ) in the presence or absence of PIBF (2.0 μg/mL) administered intraperitoneal on GD 15 to sFlt-1 induced hypertensive pregnant rats. Mean arterial blood pressure (MAP), placental and endothelial mt ROS and function were measured on GD 19. Infusion of sFlt-1 into NP rats increased MAP to 112 + 2 (n=11) compared with control NP rats 98 + 2 mmHg (n=15, p<0.05). Administration of PIBF reduced MAP to 100 + 1 mmHg in the presence of sFlt-1(n=5, p<0.05). Mt ROS in placenta was 108 + 6 in NP (n=4), 429 + 32 in NP+ sFlt-1(n=3) and reduced to 234 + 15 in NP+ sFlt-1+ PIBF (n=3). State 3 respiration, which is indicative of ATP production, was reduced in placentas of sFlt-1 infused rats versus NP, but was improved with PIBF. Moreover, sera from NP+sFlt-1 treated with PIBF attenuated endothelial cell mtROS ( 29 + 8 % gate) compared with sera from NP+sFlt-1 (54 + 15 % gate (n=4)). Our study indicates a role of sFlt-1 induced hypertension during pregnancy to reduce placental and endothelial cell mt function. Importantly, supplementation of PIBF improved mt function and ROS which was associated with improved blood pressure in sFlt-1 induced hypertensive pregnant rats indicating the efficacy of improved progesterone signaling as a potential therapeutic for PE.